BBC News also reported that the fifth member of their group was imprisoned back in March following a bomb hoax.
"The hoaxes may have seemed harmless to them, but they caused genuine distress to a number of members of the public, who should be able to go about their daily business without being put in fear in this way. We hope these convictions send a strong message that unlawful activities such as these will not be tolerated in London," said Robert Short, of the Crown Prosecution Service.
The fifth member arraigned was Danh Van Le. He was sentenced to 12 weeks imprisonment in March for his involvement in the fake robbery. He was also sentenced to 24 weeks in jail for a separate bomb hoax.
Mr. Jarvis was sentenced to 20 weeks, Mr. Mensah and Mr. Gomes to 18 weeks each, and Mr. Ferizolli to 16 weeks for the charge at the National Portrait Gallery. They were also sentenced to eight weeks for the fake kidnapping at Tate Britain, which is set to run concurrently.
The group is now evaluating their methods, according to BBC News.
"Our aim was never to get away with breaking the law," a member of the group known as Light told the BBC at the time. We are a big influence and we try to use that positively," he said of the channel's large following.
Although the group claimed that the pranks were done simply to entertain their audience and they had no intention of spreading fear among the public, the court viewed the case differently than they perceived.